Lean systems

Many business processes and especially manufacturing are based on serial
processes, where things are passed down a chain of processes, with value
being added at each point. Within this system there is massive opportunity
for inefficiency and waste, such as buffer stores, things getting lost,
breakdowns, etc.

A lean system has none of this fat. Going lean means removing all waste
from the system. This has many implications, such as:

Gaining a true understanding how things work so you can constantly
improve, reduce waste and increase efficiency.

Reducing buffer storage to the absolute minimum, which makes
everything connected: if one point in the system breaks down, everyone
is very rapidly also affected.

Attention to bottlenecks, including when up-stream to suppliers and
downstream to customers.

Being able to rapidly change the system to work on different
products.

Having flexible, multi-skilled people who can perform such changes.

Having systems and management that engenders such a capable and
motivated workforce.

Thus parts and material should arrive at any point just as they are
needed, and not before. This is known as Just In Time (JIT) and is
the perfection that is sought, and can be far more closely attained than
old systems which use large buffer stores to cover up inefficiencies in
the system. JIT principles have been adopted in many other areas further
afield from the original factory floor. For example Just In Time software
compilers compile code just before it is needed.

Toyota is consistently recognized as a leader and originator in this
methodology (which helps to explain why many of the terms associated with
it are Japanese).